Adjustable rafter square



"Oct 13, 1959 R. VARBEI. 2,908,080

ADJUSTABLE RAFTER SQUARE Filed April s. 1954 RoberL. Varbe/ IN V EN TOR.

42 Y 43' 26 2'2 v BY 9W 9ms ,States `1,afff1u O f ,2,908,0`so- ADJUSTABLE SQUARE Rberf L. varier, oklahoma' city, okla. .i "Application April 3,1954, sesame. 421,801 wz claims. (ci. sse-9s) This invention 'relates' to an adjustable rafter square and particularlyjto a birds mouth gauge type square in which the birds mouth may be adjusted for cutting birds mouth in rafters for various pitch of rafter.

In the operation of preparing rafters for roofs, it is customary to provide .aso-called .birds mouth cutin the bottom end of a -ra-fter. for vconnection'with the plate of a building .soy that the rafter will properly fit when inclined in the properpitch. The laying out of birds mouth cuts by means of the usual steelsquare is a matter of great skill and experience. Heretofore various types of birds mouth ga'uges have been provided for laying out and marking the birds ymouth cut. u

. The present invention .provides a birds mouth square irrA which :the birdsmouth may be` lreadily adjusted to various pitches so thatthe device may be readily reset and 5. laying out the cu-t 18. First arm 24 has `afiir'st part and a second part 25 on opposite sides of rivetf`28.f Second arm 26 has a rst part 27l and a` -secondlpantfl'29- ice with vthe top surface of a plate 16 anda surfaceldfor contact with the side of the plate so that lthe rafter may be rigidly and firmly supported on the plate. Likewise,

the rafter 10 isp'rovided with avvertical cut 20 so vthat thek pair of raftersmaybe rigidly and firmly ljoined 'togetherat the comb.

and a second arm- 26 which are rigidly connected together by means of the rivet 28 so Ithat the arms 24 and 26 are rigidly secured together in exactly perpendietllarA relationj to each other to provide fthe birds `mouthliaving the s face 30 -for laying out the cut 14 and the surface 132i on opposite sides of rivet 28.'4

The arm 24 extends outwardly from the juiicftibnYofv v the birds mouth and is provided with a pivotal connection 36 with the base bar 22. Likewise, thepar`m26 is extended rearwardly from the birds mouth and Iengages in sliding relation with the bar- -22. A Vguide bar 38fisV i fasteners such as rivets y44 and 446. The spacersAQ and lockedin set'position so that thecarpenter may mark out e.

a plurality of birds mouth cuts allat exactly the same angle so that the pitch of all of the rafters will be identical. --Further the birds -mouth gauge may be utilized to cut the plumb at the top of the rafter so that it will be lan exact meet with the opposed raf-ter.

' In the construction according to the invention, a base bar is provided for contact with one edge of a rafter and a square or birds mouth is provided by means of a pair of crossed strip members which are rigidly connected together in square relation with one of the strip members being pivotally connected to the base bar and the other strip member extending in sliding relation therealong so that the pivoted member may be adjusted to any desired angle. A guide is rthen provided by means of a separate bar arranged in spaced relation to Ithe base bar and locking means are provided in the guide bar `for securing the sliding arm of the birds mouth in adjusted position.

Accordingly, an object of the invention is to provide an improved rafter square.

It is a further object of the invention to provide a rafter square which may be adjusted to any desired pitch.

It is a further object of the invention to provide improved means of ylocking a birds mouth gauge in pitch relation. Other objects and many of the 4attendant advantages of the present invention will be apparent from the :following detailed description, taken in conjunction with the accompanying drawing, in which:

' Figure 1 is an illustration of a rafter in position showing the birds mouth cut and the necessary plumb cut;

Figure 2 is a plan view of the birds mouth gauge according to the invention;

Figure 3 is a similar view of the birds mouth gauge set to cut the birds mouth of Figure 1 and shown applied to the rafter;

Figure 4 is a similar view showing the utilization of the adjustable square to produce the plumb cut; and

Figure 5 is an enlarged sectional view through the locking mechanism of the device.

In the exemplary embodiment according to the invention, a rafter 10 is provided with a birds mouth cut 12 which is designed to provide a surface 14 for contact 42 either with or `without the guide,y bar 38 constitute means by which to limit the pivotal movementfof-,arms Z4'and 26 by engagement of a part `of arm 2 6with the. spacers.` The bars 22 and'38, together withiilhelspacer members 40 and 42, define a longitudinal slot through the extension ofthe' arm 26 is' freely slidablze".4 Obviously, by sliding` the arm 26 in the" `slt 48;" the birds mouth may be pivoted about the point 36 to determine the pitch of the birds mouth cut to be laid out thereby.

In order to be able to properly adjust the birds mouth with ease :and dispatch, a gauge platev 50 is rigidly attached to the bar 22 and extends outwardly on the opposite. side from the birds mouth. The front surface of dial 50 is in a plane parallel to the at side wall of base bar 22. The arm 24 is provided with a pointer 52 which extends over a scale 54 on the plate 50. The scale 54 will be laid ofi in indicia corresponding to the various pitches to belaid out by the birds mouth. Preferably, the indicia is provided in the lform of a column 56 at one side of the scale and connected to the scale by means of suitable leader lines 58.

In order -to secure the device in xed relation, suitable locking means such `as set screws 60` are provi-ded in the guide plate 38 so that when the pointer `52 has been moved to the exact position desired on the scale 54 the set screw 60 will be tightened into engagement with the arm 26 to rigidly secure the same in place so that any desired number of birds mouths may then be marked and cut Without disturbing the setting.

In the utilization of the device to cut a birds mouth, the device will be set as shown in Figure 3 with the pointer corresponding to the indicia 12-12 showing a run of 12 and an elevation of 12 as shown in Figure 1. Suitable set screws 60 will then be placed in tight relation 'with the arm 26 so that the cut may be laid out and marked as shown at 62 in Figure 3.

In order to utilize the device to make the plumb cut at the top of the rafter, the device will be Iset in the same manner as indicated in Figure 3 so that fthe plumb cut 20 will be exactly parallel to the cut 18 and the cut will be marked as shown at 64 in Figure 4.

To determine proper length of rafter on any desired pitch of roof, after the pointer 52 is set on the dial 54, locate the corresponding figure on the scale 70 on lower Patented oci., 1.3., e;

Y 3 v end of base bar 22, then measure the exact distance in inches from this figure to the upper endofbase bar 22, then multiply this length by one-half the width lof the buil ',ng, from outer edge of wa1ls,thereby giving the:

e'xct length of raftermentlpqfkfthpe device has been shown and'described accord: ingle, thabest present understanding thereof- However, itwillebe apparent lto those skilled inthe art thatvarious changes and modifications inthe construction and arrangementfofn the' parts thereofA mayk be readily resorted to witho 'departing from the true spirit and scope of the, inveatmnf, i'

-Wha-t is claimed as new is as follows:V

1j adjustable rafter gauge Consisting 0fA a flat elonbflSe b ar having a datl sidewall, a graduatedV dial protrudingffrompanedge of. saidlbasebar and having a frontsurface'whichis in a plane, parallel tosaid at side wallof saidjbanja first arm, a second arm, means joining. savilzarrns VinQixed relationship to keach `other'and at rightpjangles, said first arm havingv -a 'rst partrprotrudng from saidarrns fixing means at one side thereof 'and pro- IVidedwitlrl an'extension Whichris movable over the graduationshon said dialin order to constitute an indicator, ysaid first armhaving a second part protruding fromsaid arms @ximg means at the other side thereof, a pivot pin connectingsaid f-rst part of said rst arm to saidbase bar and ho' 'ngi said rst arm with` the surface thereof Hush a ,nstsaid basebar and thereby enabling said rst arm tolbelpivotally swung with respect to said base bar and tllgeindiator pointing to diiferent, graduations on -said dial toindicate the angularity of said arms with respect to,said base bar, said second arm having a firstv part prortruding 'from oneY side of said arnrs xing means, said rst part of saidv second arm and said second part of saidirst arm having confronting'edgres that are arranged atfnght angles to each other andk that constitute` a-birds F r purpose of' exempliiication, a particular embodi-- mouth by which to guide a scriber in Ina-king similar, representations, said second arm having ya second part' protruding from the opposite side of said arms fixing means and fitting ush against said at wall of said base bar, means extending generally parallel to said base bar and terminating between said pivot which connects said trst part of said rst arm to said base bar and the remote end of said base bar for limitingthe extent of pivotal movement of said-arms with respect to-said base bar by contact of opposite edges of said second par-t of the second armA therewith. s

2.. The adjustable rafter gauge-of. c laim,1, wherein said limiting means comprise a Ulshaped guidethrough,

which said secondpart of said s ecnndarm is passed, and adjustable means carried by said guide and engageable with said second part of said second arm for locking said second part of said second arm and thereby Ilocking both Y of said arms in theselectedadjustedposition.l

ReferencesV Citedin the file of this-patent`H UN1rEDsTATEsPATENTs i Bast- .Aug. 25,1891

'485,456 YCook Nov. 1,-,12892 718,817V Caldwell. et. al. Jan. 20,' 1903;

743,900. Mahan Nov.,10`, 1903i 830,322 Hodge Sept. 4, 19.06,v 1,282,999. Y Wall ,Octt' 29, 191,8" 1,365,991 Helden Jan.l 18, 1921,` 1,553,265 Reppe Sept. 8, 1925V 1,852,277 Y Wheeler Apr. 5, 1,932.` 1,947,448 l Ahola. Feb. 20, 11934 1,983,516.: f Ahola, Dec. 1,1, 1934i 2,090,8351 .,Gardha-m Aug. 1937` Y2,574,035 Heiskell Nov. f6, 1951:" 

